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| author | Ralf Baechle <ralf@linux-mips.org> | 2006-09-28 04:45:21 +0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2007-02-14 01:40:50 +0300 |
| commit | f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f (patch) | |
| tree | 2405e012e079693e0fcfde9ff981c549d6c68a21 /include/asm-mips/bitops.h | |
| parent | 509cb37e173d4e39cec47238397e91b718730794 (diff) | |
| download | linux-f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f.tar.xz | |
[MIPS] Improve branch prediction in ll/sc atomic operations.
Now that finally all supported versions of binutils have functioning
support for .subsection use .subsection to tweak the branch prediction
I did not modify the R10000 errata variants because it seems unclear if
this will invalidate the workaround which actually relies on the cheesy
prediction of branch likely to cause a misspredict if the sc was
successful.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'include/asm-mips/bitops.h')
| -rw-r--r-- | include/asm-mips/bitops.h | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/include/asm-mips/bitops.h b/include/asm-mips/bitops.h index 06445de1324b..06c08228a525 100644 --- a/include/asm-mips/bitops.h +++ b/include/asm-mips/bitops.h @@ -68,7 +68,10 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr) "1: " __LL "%0, %1 # set_bit \n" " or %0, %2 \n" " " __SC "%0, %1 \n" - " beqz %0, 1b \n" + " beqz %0, 2f \n" + " .subsection 2 \n" + "2: b 1b \n" + " .previous \n" " .set mips0 \n" : "=&r" (temp), "=m" (*m) : "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m)); @@ -116,7 +119,10 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr) "1: " __LL "%0, %1 # clear_bit \n" " and %0, %2 \n" " " __SC "%0, %1 \n" - " beqz %0, 1b \n" + " beqz %0, 2f \n" + " .subsection 2 \n" + "2: b 1b \n" + " .previous \n" " .set mips0 \n" : "=&r" (temp), "=m" (*m) : "ir" (~(1UL << (nr & SZLONG_MASK))), "m" (*m)); @@ -166,7 +172,10 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *addr) "1: " __LL "%0, %1 # change_bit \n" " xor %0, %2 \n" " " __SC "%0, %1 \n" - " beqz %0, 1b \n" + " beqz %0, 2f \n" + " .subsection 2 \n" + "2: b 1b \n" + " .previous \n" " .set mips0 \n" : "=&r" (temp), "=m" (*m) : "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m)); @@ -222,8 +231,12 @@ static inline int test_and_set_bit(unsigned long nr, "1: " __LL "%0, %1 # test_and_set_bit \n" " or %2, %0, %3 \n" " " __SC "%2, %1 \n" - " beqz %2, 1b \n" + " beqz %2, 2f \n" " and %2, %0, %3 \n" + " .subsection 2 \n" + "2: b 1b \n" + " nop \n" + " .previous \n" " .set pop \n" : "=&r" (temp), "=m" (*m), "=&r" (res) : "r" (1UL << (nr & SZLONG_MASK)), "m" (*m) @@ -290,8 +303,12 @@ static inline int test_and_clear_bit(unsigned long nr, " or %2, %0, %3 \n" " xor %2, %3 \n" " " __SC "%2, %1 \n" - " beqz %2, 1b \n" + " beqz %2, 2f \n" " and %2, %0, %3 \n" + " .subsection 2 \n" + "2: b 1b \n" + " nop \n" + " .previous \n" " .set pop \n" : "=&r" (temp), "=m" (*m), "=&r" (res) : "r" (1UL << (nr & SZLONG_MASK)), "m" (*m) @@ -356,8 +373,12 @@ static inline int test_and_change_bit(unsigned long nr, "1: " __LL "%0, %1 # test_and_change_bit \n" " xor %2, %0, %3 \n" " " __SC "\t%2, %1 \n" - " beqz %2, 1b \n" + " beqz %2, 2f \n" " and %2, %0, %3 \n" + " .subsection 2 \n" + "2: b 1b \n" + " nop \n" + " .previous \n" " .set pop \n" : "=&r" (temp), "=m" (*m), "=&r" (res) : "r" (1UL << (nr & SZLONG_MASK)), "m" (*m) |